Various strains of HSV have been observed to express different reactivation patterns in the rabbit keratitis model. This suggests that specific viral information may be critical to the recurrence frequency observed in the eye. The objective of the experiments outlined below is to define the specific HSV DNA fragments or polypeptides responsible for HSV reactivtion. The methods utilized take advantage of observed differences in endonuclease cleavage and polypeptide electrophoretic mobilities of HSV-1 and HSV-2 strains to map polypeptides as well as the reactivation phenotype on the physical map of HSV DNa. In addition, the variety of HSV strains isolated in keratitis will be defined by their endonuclease cleavage patterns and attempts will be made to relate specific strains to their clinicoepidemiological behavior or host responses.